Security updates are made by the maintainer; they may not be
effective on all architectures, and may be delayed. Packages uploaded
may not meet release standards, but any breakage is expected to be fixed
promptly. Updates are made by maintainers.

experimental

Packages that are not suitable for widespread use yet. They may
or may not meet release standards, as it is commonly used as a staging area
for uploads to unstable. Updates are made by maintainers.